4 * This file is part of BeRTOS.
6 * Bertos is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * As a special exception, you may use this file as part of a free software
21 * library without restriction. Specifically, if other files instantiate
22 * templates or use macros or inline functions from this file, or you compile
23 * this file and link it with other files to produce an executable, this
24 * file does not by itself cause the resulting executable to be covered by
25 * the GNU General Public License. This exception does not however
26 * invalidate any other reasons why the executable file might be covered by
27 * the GNU General Public License.
29 * Copyright 2003, 2004, 2005, 2006 Develer S.r.l. (http://www.develer.com/)
30 * Copyright 2000, 2008 Bernie Innocenti <bernie@codewiz.org>
33 * \brief Hardware independent timer driver (implementation)
36 * \author Bernie Innocenti <bernie@codewiz.org>
41 #include "cfg/cfg_timer.h"
42 #include "cfg/cfg_wdt.h"
43 #include "cfg/cfg_kern.h"
45 #include <cfg/debug.h>
46 #include <cfg/module.h>
49 #include <cpu/types.h>
53 * Include platform-specific binding code if we're hosted.
54 * Try the CPU specific one for bare-metal environments.
57 #include OS_CSOURCE(timer)
59 #include CPU_CSOURCE(timer)
63 * Sanity check for config parameters required by this module.
65 #if !defined(CONFIG_KERNEL) || ((CONFIG_KERNEL != 0) && CONFIG_KERNEL != 1)
66 #error CONFIG_KERNEL must be set to either 0 or 1 in config.h
68 #if !defined(CONFIG_WATCHDOG) || ((CONFIG_WATCHDOG != 0) && CONFIG_WATCHDOG != 1)
69 #error CONFIG_WATCHDOG must be set to either 0 or 1 in config.h
77 #if CONFIG_KERN_PREEMPTIVE
78 #include <hw/switch.h>
80 #if CONFIG_KERN_SIGNALS
81 #include <kern/signal.h> /* sig_wait(), sig_check() */
82 #include <kern/proc.h> /* proc_current() */
83 #include <cfg/macros.h> /* BV() */
89 * \def CONFIG_TIMER_STROBE
91 * This is a debug facility that can be used to
92 * monitor timer interrupt activity on an external pin.
94 * To use strobes, redefine the macros TIMER_STROBE_ON,
95 * TIMER_STROBE_OFF and TIMER_STROBE_INIT and set
96 * CONFIG_TIMER_STROBE to 1.
98 #if !defined(CONFIG_TIMER_STROBE) || !CONFIG_TIMER_STROBE
99 #define TIMER_STROBE_ON do {/*nop*/} while(0)
100 #define TIMER_STROBE_OFF do {/*nop*/} while(0)
101 #define TIMER_STROBE_INIT do {/*nop*/} while(0)
105 /// Master system clock (1 tick accuracy)
106 volatile ticks_t _clock;
109 #ifndef CONFIG_TIMER_DISABLE_EVENTS
112 * List of active asynchronous timers.
114 REGISTER static List timers_queue;
118 * Add the specified timer to the software timer service queue.
119 * When the delay indicated by the timer expires, the timer
120 * device will execute the event associated with it.
122 * \note Interrupt safe
124 void timer_add(Timer *timer)
130 /* Inserting timers twice causes mayhem. */
131 ASSERT(timer->magic != TIMER_MAGIC_ACTIVE);
132 DB(timer->magic = TIMER_MAGIC_ACTIVE;)
134 IRQ_SAVE_DISABLE(flags);
136 /* Calculate expiration time for this timer */
137 timer->tick = _clock + timer->_delay;
140 * Search for the first node whose expiration time is
141 * greater than the timer we want to add.
143 node = (Timer *)LIST_HEAD(&timers_queue);
144 while (node->link.succ)
147 * Stop just after the insertion point.
148 * (this fancy compare takes care of wrap-arounds).
150 if (node->tick - timer->tick > 0)
153 /* Go to next node */
154 node = (Timer *)node->link.succ;
157 /* Enqueue timer request into the list */
158 INSERT_BEFORE(&timer->link, &node->link);
165 * Remove a timer from the timers queue before it has expired.
167 * \note Attempting to remove a timer already expired cause
168 * undefined behaviour.
170 Timer *timer_abort(Timer *timer)
172 ATOMIC(REMOVE(&timer->link));
173 DB(timer->magic = TIMER_MAGIC_INACTIVE;)
178 #endif /* CONFIG_TIMER_DISABLE_EVENTS */
182 * Wait for the specified amount of timer ticks.
184 void timer_delayTicks(ticks_t delay)
186 /* We shouldn't sleep with interrupts disabled */
187 ASSERT_IRQ_ENABLED();
189 #if defined(CONFIG_KERN_SIGNALS) && CONFIG_KERN_SIGNALS
192 ASSERT(!sig_check(SIG_SINGLE));
193 timer_set_event_signal(&t, proc_current(), SIG_SINGLE);
194 timer_setDelay(&t, delay);
196 sig_wait(SIG_SINGLE);
198 #else /* !CONFIG_KERN_SIGNALS */
200 ticks_t start = timer_clock();
203 while (timer_clock() - start < delay)
210 #endif /* !CONFIG_KERN_SIGNALS */
214 #ifndef CONFIG_TIMER_DISABLE_UDELAY
217 * Busy wait until the specified amount of high-precision ticks have elapsed.
219 * \note This function is interrupt safe, the only
220 * requirement is a running hardware timer.
222 void timer_busyWait(hptime_t delay)
224 hptime_t now, prev = timer_hw_hpread();
229 now = timer_hw_hpread();
231 * We rely on hptime_t being unsigned here to
232 * reduce the modulo to an AND in the common
233 * case of TIMER_HW_CNT.
235 delta = (now - prev) % TIMER_HW_CNT;
244 * Wait for the specified amount of time (expressed in microseconds).
246 * \bug In AVR arch the maximum amount of time that can be used as
247 * delay could be very limited, depending on the hardware timer
248 * used. Check timer_avr.h, and what register is used as hptime_t.
250 void timer_delayHp(hptime_t delay)
252 if (UNLIKELY(delay > us_to_hptime(1000)))
254 timer_delayTicks(delay / (TIMER_HW_HPTICKS_PER_SEC / TIMER_TICKS_PER_SEC));
255 delay %= (TIMER_HW_HPTICKS_PER_SEC / TIMER_TICKS_PER_SEC);
258 timer_busyWait(delay);
260 #endif /* CONFIG_TIMER_DISABLE_UDELAY */
264 * Timer interrupt handler. Find soft timers expired and
265 * trigger corresponding events.
270 * With the Metrowerks compiler, the only way to force the compiler generate
271 * an interrupt service routine is to put a pragma directive within the function
275 #pragma interrupt saveall
278 #ifndef CONFIG_TIMER_DISABLE_EVENTS
282 * On systems sharing IRQ line and vector, this check is needed
283 * to ensure that IRQ is generated by timer source.
285 if (!timer_hw_triggered())
290 /* Perform hw IRQ handling */
293 /* Update the master ms counter */
296 #ifndef CONFIG_TIMER_DISABLE_EVENTS
298 * Check the first timer request in the list and process
299 * it when it has expired. Repeat this check until the
300 * first node has not yet expired. Since the list is sorted
301 * by expiry time, all the following requests are guaranteed
304 while ((timer = (Timer *)LIST_HEAD(&timers_queue))->link.succ)
306 /* This request in list has not yet expired? */
307 if (_clock - timer->tick < 0)
310 /* Retreat the expired timer */
311 REMOVE(&timer->link);
312 DB(timer->magic = TIMER_MAGIC_INACTIVE;)
314 /* Execute the associated event */
315 event_do(&timer->expire);
317 #endif /* CONFIG_TIMER_DISABLE_EVENTS */
327 void timer_init(void)
331 #ifndef CONFIG_TIMER_DISABLE_EVENTS
332 LIST_INIT(&timers_queue);
343 #if (ARCH & ARCH_EMUL)
345 * Stop timer (only used by emulator)
347 void timer_cleanup(void)
353 // Hmmm... apparently, the demo app does not cleanup properly
354 //ASSERT(LIST_EMPTY(&timers_queue));
356 #endif /* ARCH_EMUL */